LegiScan MCP Server

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A Model Context Protocol (MCP) server that gives terminal agents structured access to the LegiScan API for legislative data from all 50 US states and Congress.

Built for research workflows where you direct an agent (Codex, Claude Code, Claude Desktop, etc.) to gather bill history, sponsor context, and voting records quickly.

Features

10 Streamlined MCP Tools optimized for legislative research workflows
Composite tools that collapse multi-step research workflows into single MCP tool calls
Per-request batching and lookup caching for repeated bill and roll-call lookups
Full TypeScript type definitions for all API responses
Bill number normalization (handles AB 858, AB858, AB-858 formats)
Input validation guardrails for state codes, legislator name queries, and large bill batches

Installation

From npm (Recommended)

npm install -g legiscan-mcp-server

From Source

git clone https://github.com/sh-patterson/legiscan-mcp.git
cd legiscan-mcp
npm install
npm run build

Setup

1. Get a LegiScan API Key

Create a free account at LegiScan
Register for API access at https://legiscan.com/legiscan
Copy your API key

2. Add to Your MCP-Capable Agent

Add this server to whatever MCP host your terminal agent uses.

Claude Desktop config paths:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json

For other MCP clients (Codex CLI, Claude Code, etc.), add the same mcpServers.legiscan entry in that client's MCP config file.

Using npx (Recommended)

{
  "mcpServers": {
    "legiscan": {
      "command": "npx",
      "args": ["-y", "legiscan-mcp-server"],
      "env": {
        "LEGISCAN_API_KEY": "your_api_key_here"
      }
    }
  }
}

Using local installation

{
  "mcpServers": {
    "legiscan": {
      "command": "node",
      "args": ["/path/to/legiscan-mcp-server/dist/index.js"],
      "env": {
        "LEGISCAN_API_KEY": "your_api_key_here"
      }
    }
  }
}

Available Tools

Composite Tools (High-Level Research)

| Tool | Description | | ------------------------------- | ------------------------------------------------------------------- | | legiscan_find_legislator | Find a legislator's people_id by name. Supports partial matching. | | legiscan_get_legislator_votes | Get how a legislator voted on multiple bills in one call. | | legiscan_get_primary_authored | Get only bills where legislator is primary author (not co-sponsor). |

Bills

| Tool | Description | | ------------------------------ | ------------------------------------------------------------------------------------------ | | legiscan_get_bill | Get detailed bill info (sponsors, history, votes, texts) | | legiscan_find_bill_by_number | Find bill by number (handles AB 858, AB858, AB-858, A.B. 858). Best for exact bill lookup. | | legiscan_get_roll_call | Get vote details with individual legislator votes |

People

| Tool | Description | | ----------------------------- | ----------------------------------------------------------------------- | | legiscan_get_person | Get legislator info with third-party IDs (VoteSmart, OpenSecrets, etc.) | | legiscan_get_session_people | Get all legislators active in a session |

Search

| Tool | Description | | ----------------- | --------------------------------------------------------------------------------------------------------------------------------------- | | legiscan_search | Full-text search across legislation. Accepts bill-number variants like AB858, but use legiscan_find_bill_by_number for exact matches. |

Sessions

| Tool | Description | | --------------------------- | -------------------------------------------- | | legiscan_get_session_list | List available legislative sessions by state |

Researcher Workflow (Terminal Agent)

1. Start with a scoped request

Give your agent a goal, state, timeframe, and output format.

Example prompt:

Use the LegiScan MCP tools to find major California housing bills in the current session.
Return: bill number, title, latest action date, top sponsors, and whether there was a close roll-call vote (margin <= 5).

2. Ask the agent to follow a tool sequence

For high-quality results, tell the agent to do this order:

legiscan_get_session_list to identify the correct session.
legiscan_search or legiscan_find_bill_by_number to locate target bills.
legiscan_get_bill for sponsor/history/vote references.
legiscan_get_roll_call for individual vote details.
legiscan_get_person only when legislator enrichment is needed.

If you start with legiscan_find_legislator, keep passing the returned session.session_id or the same state into follow-up authoring workflows so results stay in the intended legislature and timeframe.

3. Reuse composite tools for analyst workflows

These cut tool-call volume and simplify instructions to your agent:

legiscan_find_legislator: get people_id from a name query.
legiscan_get_primary_authored: separate primary-authored from co-sponsored bills.
legiscan_get_legislator_votes: pull vote positions across many bills in one request.

Prompt Templates

A) Opposition research on one legislator

Use LegiScan MCP for Texas.
1) Find legislator "Jane Smith".
2) List all primary-authored bills in the current session.
3) For these bills, summarize topic area and latest status.
4) Then check votes on SB 12, HB 301, and SB 455, and show how the legislator voted.

B) Bill tracking brief for an issue area

Use LegiScan MCP to track "climate resilience" bills in New York.
Focus on current session only.
Return top 15 bills by relevance with bill number, title, last action, sponsor party, and any recorded roll calls.

C) Scorecard support workflow

For California session 2172, resolve bill numbers AB 858, SB 525, SB 616, SB 399.
For each bill, fetch details and any roll calls.
Then report vote positions for people_id values 21719, 23214, and 25359.
Output as a table suitable for CSV export.

Workflow Simplification

The composite tools dramatically reduce agent-to-tool round trips for common workflows:

| Workflow | Manual MCP Steps | With Composites | | ------------------------------------------------ | ----------------------------------------------------------------------------------- | --------------------------------------------------------- | | Get votes for 1 legislator on 10 bills | Find legislator → search/resolve bills → inspect each bill → inspect each roll call | 1 tool call once you have bill_ids | | Filter primary authored from 150 sponsored bills | Sponsored list → fetch each bill → inspect sponsors | 1 tool call, optionally scoped by state or session_id | | Find legislator by name | Session discovery → session people lookup → manual matching | 1 tool call |

Research Tips

State codes are validated as two-letter strings and uppercased automatically (ca → CA). Invalid codes like ZZ pass local validation but return an API error from LegiScan.
Always pin state and session in your prompt to reduce ambiguous results.
Ask the agent to show bill_id, roll_call_id, and people_id in intermediate output so you can audit traceability.
For legislator search, provide at least a first and last name (name input must be at least 2 characters).
legiscan_get_primary_authored can return all available sessions, but passing state or session_id keeps results aligned to the intended legislature and timeframe.
legiscan_get_legislator_votes accepts up to 100 bill_ids per request; split larger jobs into chunks.
legiscan_search retries compact bill-number queries like AB858 using a canonical spaced format. For exact bill resolution, prefer legiscan_find_bill_by_number.
Ask for final outputs in a table/CSV-ready shape if you plan downstream analysis.

Development

npm run build        # Compile TypeScript
npm run typecheck    # Type-check src + tests
npm test             # Run deterministic unit tests (no API key)
npm run test:e2e     # Run real-world workflow tests (skips cleanly without API key)
npm run test:live    # Run live API integration tests (requires API key)
npm run test:coverage # Run unit tests with coverage
npm run lint         # Check for lint errors
npm run format       # Format code with Prettier

Testing Modes

npm test / npm run test:unit: Fast deterministic tests with mocked network calls.
npm run test:e2e: Research workflow tests based on real legislative analysis tasks. Skips if LEGISCAN_API_KEY is unavailable.
npm run test:live: Real LegiScan API integration tests. Requires LEGISCAN_API_KEY.

API Limits

Free public API keys have a 30,000 queries per month limit
Composite tools batch requests (10 concurrent max) and cache repeated lookups inside a single request to avoid unnecessary duplication
Composite tools reduce MCP workflow friction, but LegiScan API usage still scales with the number of distinct bills and roll calls you inspect

Docker

Build the container image locally:

docker build -t legiscan-mcp .

Run it with your API key provided at runtime:

docker run --rm -i \
  -e LEGISCAN_API_KEY=your-api-key-here \
  legiscan-mcp

Releases

Glama checks expect a GitHub release. After merging your next repo changes, create and publish a tag such as v1.0.0 from GitHub or with:

git tag v1.0.0
git push origin v1.0.0

License

MIT - see LICENSE for details.

legiscan-mcp